ewz developed its energy concept for the Swiss Life Arena – a venue with 31,500 square metres of floor space – in line with the goals of the 2,000-Watt Society. The integrated energy solution combines environmental sustainability with economic efficiency by exploiting synergies between cooling and heating production and power generation within a sophisticated building services system.
- 28,000 m² site
- Total capacity of approx. 12,000 (seated and standing)
- Heat requirement of 3 GWh per year
- Cooling requirement of 4 GWh per year, of which 2.6 GWh is attributable to the two ice rinks
- Cooling for adjoining cooling network: around 3.1 GWh upon completion
- Photovoltaic electricity generation of around 0.4 GWh per year
- 100 per cent carbon-neutral, Minergie certified
- Around 650 tonnes of CO₂ emissions avoided per year
The stadium, which measures 170 metres in length and is situated in Zurich’s Altstetten district, boasts a range of distinctive features. Its unique exposed concrete façade is particularly eye-catching. This has the look of a draped curtain and was manufactured by the builder on site. It is not only a masterpiece of craftsmanship, but has also brought environmental benefits by eliminating long transport routes and keeping the added value in Switzerland.
However, the facade is not the only area where sustainability was prioritised. When developing its energy concept for the Swiss Life Arena (in German), ewz was guided by the goals of the 2,000-Watt Society. The integrated energy solution combines environmental sustainability with economic efficiency by skilfully exploiting synergies between cooling production and the resulting waste heat.
However, the complex building services at the Swiss Life Arena are not the only reason for its high energy efficiency. Right from the outset, the architects designed the structure to minimise resource consumption during both construction and operation. In combination with the sophisticated building services system, the Swiss Life Arena meets the Minergie standard, which signifies recognition of its outstanding performance in energy efficiency, comfort and climate protection.
The certificate is testament to the ongoing commitment of the owner and operator to environmentally friendly practices and innovative energy solutions. Efficient building technologies, renewable energy sources and a high level of indoor environmental quality for athletes and guests alike are central elements of the sustainable approach.
Ice rinks at the heart
The two central ice rinks constitute the heart of the arena. The training rink and main rink also form the core of the energy concept. The energy centre serves as the control hub for cooling and heat production. This is where the cooling is generated for the ice and also for the air-conditioning system that dehumidifies the stadium’s indoor air. Environmentally friendly ammonia is used as a refrigerant for the main rink, which ensures that the ice surface is very high quality. A water-glycol mixture flows through the pipes of the training rink.
Cooling is also required for dehumidifying rooms and for air conditioning. Humidity is always a problem during matches at ice rinks, because the stadium quickly becomes packed with spectators, who give off a lot of body heat. Cooling is used to cool the humid air down to the dew point, the moisture is collected and drained away, and the dry air is then reheated. This process is demand-driven and controlled by sensors. The ancillary rooms, such as the restaurant, conference rooms or physiotherapy rooms, are air-conditioned using a thermal component activation system. A piping system embedded into the walls and ceilings activates the building mass, making it possible to control the temperature of these rooms in a gentle, draught-free way.
When you produce cooling, you also generate heat – a welcome side effect. In the arena, we use the waste heat from ice production for heating. A heat pump prepares the hot water. A low-temperature network sends heat to the underfloor heating. We provide hot water and water for ice preparation via the high-temperature network.
The Swiss Life Arena is connected to the Altstetten and Höngg energy network’s anergy network, thereby enabling loss-free energy management. The energy network uses treated waste water and waste heat from the sludge incineration plant of the Werdhölzli sewage treatment plant as its primary heat sources. If the cooling production process at the Swiss Life Arena results in excess heat, any surplus not required on site is likewise fed into the anergy network. The cooling machines at the Swiss Life Arena also produce cooling for the surrounding office buildings. This ‘cooling hub’ for third parties is another sensible solution given the growing cooling requirements and the exploitation of synergies through the existing infrastructure.
Buildings and technology designed for energy efficiency
The linking of the anergy and district cooling networks creates numerous synergies in the supply of environmentally friendly heating and cooling to the stadium and its surrounding areas.
Since commissioning, ewz has been responsible for the energy-efficient operation of the systems. A remote monitoring system allows us to intervene quickly and resolve faults if and when required. The integrated building automation system, which ensures demand-driven control of the systems and efficient operation, also plays a key role. One of the biggest challenges for ewz lay in optimising coordination of the various building services components and integrating the arena into the Altstetten and Höngg energy network.
Always reliably supplied – with electricity from 100% renewable sources
The electricity consumed at the Swiss Life Arena is 100 per cent carbon-free and comes from renewable sources such as wind and water. In addition, a 440 kWp photovoltaic system is installed on the roof, producing around 400 MWh of electricity annually, depending on the amount of sunlight. All of the solar power is used for operating the power generation plant, including the heat pumps, and for running the Swiss Life Arena. Electricity production is measured by meters every quarter of an hour and divided between the two recipients, the ZSC Stadium (stadium operation) and ewz (energy centre operation), according to current requirements.
The arena and the ewz energy centre are supplied with medium-voltage power from the ewz distribution network. In addition, ewz has concluded a contracting agreement with ZSC Immobilien AG covering the construction, operation and financing of the high-voltage consumer facility for the arena. The transformer station is integrated via a medium-voltage ring of the ewz substation, supplies the downstream medium-voltage system of the energy centre and includes energy measurement, transformation to the customer's low-voltage systems and connection to the ewz control centre. This means that any change in status or malfunction is detected around the clock. In an emergency, the ewz on-call service intervenes.
